I have just seen in an electronics weekly paper that Philips have filed a case in American courts against 6 companies for I2C patent infringements. I cannot remember all the company names but Analog Devices and Cypress were mentioned. Microchip was not mentioned. It was not clear from the article exactly what was infringed, but it did mention that there something like 38 licensees of the patent.

The numbers and names above are being quoted from memory after wandering back from the company library, so all disclaimers qualify for the accuracy of these.

On Wed, 11 Oct 2000, Alan B. Pearce wrote:
> I have just seen in an electronics weekly paper that Philips have
> filed a case in American courts against 6 companies for I2C patent
> infringements. I cannot remember all the company names but Analog
> Devices and Cypress were mentioned. Microchip was not mentioned. It
> was not clear from the article exactly what was infringed, but it did
> mention that there something like 38 licensees of the patent.

> I have just seen in an electronics weekly paper that Philips have
> filed a case in American courts against 6 companies for I2C patent
> infringements. I cannot remember all the company names but Analog
> Devices and Cypress were mentioned. Microchip was not mentioned. It
> was not clear from the article exactly what was infringed, but it
> did mention that there something like 38 licensees of the patent.

Alan:

There's a reason that the six companies named in the suit never
licensed the I2C patent: Each of those companies has its own large
patent portfolio that protects it from infringement suits.

It works like this (I'll use Cypress as an example, since I'm
familiar with their patents):

Philips files suit against Cypress Semiconductor for
infringement of the I2C patent.

Cypress reminds Philips that a jury might easily be convinced
that Philips is currently infringing upon Cypress's USB patents.

A couple of weeks later, it's announced that Philips has dropped
its case against Cypress... And, by the way, Cypress and Philips
have signed a patent cross-licensing agreement.

Microchip wasn't named in the suit because they are an I2C licensee.
I assume that they weren't a licensee when they FIRST introduced I2C
devices -- if you look back at the old Microchip data books, you'll
see that they called the thing a "two-wire interface" and never used
the term "I2C" ANYWHERE -- but they clearly DID acquire a license
eventually... Probably by signing Philips' standard 2%-royalty
agreement.

Does the I2C patent apply only to semiconductor devices (eg micros)
impelementing the protocol, or to a product which can be interfaced via I2C?
e.g if I designed and sold a product with a PIC in it and used the PIC's I2C
interface so that my product could be externaly configured/monitored etc,
would I have to pay royalties? I've seen many IC's with reference to "2
wire interfaces", presumably this is an attempt to get around liscencing
issues?

I always presumed that if I bought a PIC or whatever registered I2C
chip, then I have already paid royalties to Philips and are allowed to
use I2C. So Microchip paid Philips to use I2C in any chip so that their
customers can use it.
If you manufacture chips and use I2C without paying royalties or call it
another name, then I can see cause for concern.

>Does the I2C patent apply only to semiconductor devices (eg micros)
>impelementing the protocol, or to a product which can be interfaced via I2C?
>e.g if I designed and sold a product with a PIC in it and used the PIC's I2C
>interface so that my product could be externaly configured/monitored etc,
>would I have to pay royalties? I've seen many IC's with reference to "2
>wire interfaces", presumably this is an attempt to get around liscencing
>issues?
>
>Cheers
As Microchip are a licensee, you should be covered by their license,
certainly if you're using an I2C PIC - maybe different if doing it in
software on a non-I2C part.

> As Microchip are a licensee, you should be covered by their license,
> certainly if you're using an I2C PIC - maybe different if doing it in
> software on a non-I2C part.

This issue came up on the AVR list a couple of weeks ago and was also
discussed at a Philips seminar I attended.
Someone on the AVR list emailed a Philips IP attorney and got a
response saying that they will be putting more information about the
licensing on the web page. It's not covered very well at the moment.
I've also asked Philips for a list of licensees as that doesn't seem
to be published anywhere.

The bottom line seems to be that if you have any licensed component
on your I2C bus, you are granted a license to use the bus. So you may
have 17 FPGA's and a 32 byte EEPROM and you're covered.
However, if you take the EEPROM off, you wouldn't be covered. If the
comms between the chips just stays within your board then who's to
say what it is or isn't so it's a non-issue. If you sell it as having
an I2C interface or a two wire interface that looks like I2C, you
can expect a knock on the door.

Andrew Warren made a good point though. Strategic suing is
standard practice in this industry. It seems to be the Silicon Valley
equivalent of leaving a business card at reception.